Hi I'm here to show you how to get yourself OP on cracked servers that use xAuth.
Note: some servers have gotten past this glitch it won't work 100% of the time.

Step 1. Find a cracked server and see if it runs on the plugin xAuth, (you can see by typing /pl)

Step 2. Find the name of an op (ex. MrAdmin)

Step 3. Use a cracked launcher to login as the admins name which in this case is MrAdmin ( I reccomend using the briefing client Nodus to login with that name)

Step 4. Open another window for minecarft and sign in as the admins name again

Step 5. Log into the server as the admin, it should keep annoying you saying to do /login

Step 6. Type /login and any random letters, it will say incorrect password

Step 7. Log into the server with the second mine craft window with the same name

If done correctly it should stop annoying you to do /login

Note: you shouldn't be able yo anything but walk around so when at this point just type /op yourusername